The rapid advances in human genome sequencing has generated a large amount of data and consequently a large number of hypotheses. For psychiatric disease, a number of landmark studies have led to lists of genetic variations that are linked to specific diseases. However, functional testing of these hypotheses has remained challenging due to a lack of appropriate model systems and high-throughput functional assays. Here we propose to develop and apply a series of high-throughput genome perturbation methodologies to enable the rapid identification of causal genetic variants from large-scale genetics data. The technology we propose to develop will be very broadly applicable and has the potential to radically transform the scale and rate of discovery across different biomedical fields. Three complementary technologies will be developed as a part of this proposal: 1. Functional screening methods to enable rapid identification of reprogramming factors for specific cell types. By using genome-scale transcription activation or epigenetic reprogramming libraries, we will establish a systematic approach to reverse-engineer the sufficient combinations of reprogramming factors for neuron subtypes that are relevant for different neuropsychiatric diseases, such as parvalbumin positive interneurons in schizophrenia. 2. Large-scale and systematic genome perturbation tools to enable massively-parallel functional testing of genetic variants, to enable narrowing of the long lists of correlated genetic variants to a short list of causal variants. We will establish genetic perturbation technologies to enable multiplex and systematic deletion or mutational analysis of coding and non-coding genomic regions, as well as probing of their epigenetic states, to identify causal genetic variants. 3. Efficient and precise genome modification technologies to enable rapid introduction of causal variants into cellular or animal models to enable elucidation of their disease-causing mechanisms. Whereas nuclease-based genome editing systems enables efficient gene knockout, gene insertion or gene correction remains inefficient. We will characterize a novel programmed genome rearrangement mechanism and develop it into a technology for efficient and precise mammalian genome editing. This will significantly accelerate the generation of cellular and animal models Given the broad applicability of this technology, the impact of this proposed work will be far reaching and will radically transform existing experimental approaches for studying gene interactions in all fields of life science and medicine.